Note: sometimes, a full box-in-box construction will be necessary

Suspended acoustic rafts explained

Have you ever wondered what suspended acoustic rafts are and how they acoustically work?

This page briefly explains:

• what suspended acoustic rafts are exactly
• which sound absorption performances acoustic rafts achieve and, most importantly, how they should be specified
• which materials are usually used for acoustic rafts
• examples of acoustics rafts products available on the market

What are suspended acoustic rafts?

Suspended acoustic rafts are free-hanging and flat elements made with a thick fibrous or porous materials that have sound absorption qualities. You hang them horizontally at a certain distance from a hard surface (usually a soffit).

They are a popular option to reduce the sound reverberation in:

• education spaces
• office spaces
• assembly spaces
• public spaces (such as receptions, entrance halls, etc)

Brief description of suspended acoustic raft systems

Although acoustic rafts are mostly square or rectangular, some of them are also round, oval or any other bespoke shape.

Some raft manufacturers/suppliers give the option to include lighting and other electrical systems within the rafts.

Sound absorption performance of suspended acoustic rafts

The sound absorptive materials used for suspended acoustic rafts generally achieve sound absorption Class A, Class B or Class C.

However, you should know that sound absorption classes are generally for a materials fixed to a hard surface with only one side visible. This side is the only one that absorbs sound. The other one doesn’t.

For acoustic rafts, it is a little bit different.

Suspended acoustic rafts – Sound absorption below and above

Not only the underside of the rafts absorbs sound, but also upper side indirectly.

Sound will first hit the hard surface above the acoustic rafts and then the upper side of the rafts.

Therefore, the distance between the rafts and the hard surface above has an influence on the sound absorption of the raft systems. Below approximately 1m, the further the rafts from the hard surface, the higher the sound absorption at mid and high frequencies.

Sound absorption below and above the rafts

Suspended acoustic rafts – Sound absorption of the edges

The edges of the rafts also absorb sound.

So a couple of large acoustic rafts absorb a little bit less sound than a few smaller acoustic rafts (with the same amount of absorptive materials).

Sound absorption of raft edges

Suspended acoustic rafts – Examples of sound absorption performances

To illustrate this, the graphs below shows examples of sound absorption performance for various raft systems.

  Note: for rafts, the sound absorption performance is qualified in terms of equivalent absorption area per unit. Not in terms of sound absorption coefficient per m² of material.

Equivalent absorption area (m²) of 1200mm x 1200mm acoustic rafts located at different distances from the hard surface above 200 mm, 400 mm and 1000 mm and spaced 500 mm apart (Courtesy of Ecophon)

Sound absorption per m² of raft based on rafts of different sizes hung at 1000mm from the hard surface above

(Courtesy of Ecophon)

Suspended acoustic rafts – Specification

Based on the above, you can now understand that the sound absorption characteristics of raft systems don’t just depend on the material of the rafts.

Therefore, in the acoustic specifications, it is important to include the following information:

• the sound absorption of the material installed in a room (when measured in line with ISO 354:2003 Acoustics — Measurement of sound absorption in a reverberation room)
• the size of the rafts
• the spacing between the rafts
• the distance between the rafts and the hard surface above.

  Note: the above is applicable to any other free hanging suspended acoustic system.

Materials used for suspended acoustic rafts

The materials preferred for acoustic rafts are usually thick fibrous or porous sound absorptive materials such as:

• fibre glass
• mineral wool
• wood wool and mineral wool on top
• polyester fibres
• wood fibres

Sometimes, the sound absorptive material is wrapped in a fibrous fabric or even painted.

Examples of suspended acoustic rafts

To find examples of suspended acoustic raft products, visit the Acoustic Design Catalogue here.

Acoustic plaster systems explained

Have you ever wondered what acoustic plaster systems are?

This post explains:

• What are acoustic plaster sytems?
• Advantages and uses of acoustic plaster systems
• Configurations and characteristics of acoustic plaster systems
• Sound absorption / acoustic absorption of acoustic plaster systems
• Sustainability of acoustic plaster systems
• Installation and workmanship for acoustic plaster systems
• Examples of acoustic plaster products available on the market

  Note: Although acoustic plaster systems do look really good, they might not be the solution if you are on a tight budget. Some of the reasons are because they include some high-end materials and have to be installed by specialists.

What are acoustic plaster systems?

Acoustic plaster systems are sound absorbing systems that are made of fibrous and porous materials to help reduce sound reverberation within spaces.

Advantages and uses of acoustic plaster systems

Acoustic plaster systems are usually installed on the ceilings, the soffits and sometimes the walls.

Their advantages are:

• they have a seamless and smooth appearance.
• they can be curved or shaped to follow a custom design.
• they can sometimes integrate heating and cooling systems.
• although white is preferred most of the time, they can be tinted or painted (with approved paint) in different colors.

Acoustic plasters are generally fire-resistant and can be made moisture resistant.

Lighting systems, sprinklers and audio systems can also be integrated.

Slide the images in the gallery below to see what acoustic pasters look like. To find examples of acoustic plaster products, visit the Acoustic Design Catalogue here.

Configurations and characteristics of acoustic plaster systems

Acoustic plaster systems usually come in pre-made panels that require final finishing on site.

They usually include the following:

• a thick sound absorptive backing layer made of mineral wool, glass fibre, natural fibre or foam.
• a porous (acoustically transparent) and more rigid base layer.
• a thin finish layer of plaster trowel or spray applied to the backing layer.
• a second thin layer can be applied to provide a finer finish.

The thickness of the panels ranges from approximately 10mm to 70 mm.

They can either be fixed to a hard surface or as part of a suspended ceiling (in which case, the thickness of the whole system can reach approximately 220 mm).

Sound absorption / acoustic absorption of acoustic plaster systems

The sound absorption performance of acoustic plasters depends on:

• the material of the backing layer.
• the thickness of the backing layer.
• the porosity of the surface finishes.
• if fixed to a suspended ceiling, the depth of the ceiling cavity.

The sound absorption characteristics of acoustic plasters are considered for each square meter of material and can achieve a large variety of performances ranging from Class D to Class A. 

  Note: The sound absorption characteristics of acoustic plasters increase with the thickness of the panels, the size of the cavity behind the panels and the presence of a backing layer behind the panels.

As mentioned above, plasters can also be painted provided the paint is approved by the manufacturer. This is because paint can modify the porosity of the finish layer and change the sound absorption capacity of the system.

Sustainability of acoustic plaster systems

Some plaster systems use natural or recycled materials (such as recycled glass granulate) for the backing layer.

The plaster finish can be made from cellulose, glass or marble granular aggregate, which is a secondary material obtained from the production of natural stone.

Installation and workmanship for acoustic plaster systems

Installing acoustic plaster systems requires a high level of workmanship to obtain the sound absorption performance desired and avoid cracks appearing with time.

Suppliers either have in-house and trained installers or certified installers.

Examples of acoustic plaster products

To find examples of suitable acoustic plaster products, visit the Acoustic Design Catalogue here.

Design of music rehearsal rooms – Part 3: Other general considerations for rehearsal rooms

Part 1 was going through the aspects that would make successful the acoustic design of music rehearsal rooms.

Part 2 dived deeper into acoustic design with some tips for the planning of such spaces.

Part 3 here goes through other general considerations for rehearsal rooms, including:

• answering the needs of the main performance space (within large facilities)
• facilitating access to new audiences
• providing comfort for the musicians
• turning rehearsal rooms into performance spaces
• access and practicalities

It was written by Duck Sceno (Theatre Consultants) with some contributions from Atelier Crescendo. 

Answering the needs of the main performance space

Each type of performance venue has specific needs for the rehearsals.

• Theatres and Opera houses need a room close to the dimensions of the main stage, with the possibility of installing pieces of set and creating similar light and sound.
• As well as requiring piano rooms for soloists, Opera houses also need large rooms for choirs and orchestra.
• Concert halls and Philharmonies need an (or multiple) orchestral rehearsal room(s) able to accommodate a symphony orchestra with optimal acoustic conditions.

   Atelier Crescendo’s comment: If the rehearsal room is part of a larger facility, it might be wise to locate it away from other sensitive and/or noisy areas (such as other rehearsal rooms, performance spaces, recording rooms, music practice rooms, etc). This way, you minimise the acoustic interferences between the spaces when they are used simultaneously. 

Of all the performances, opera and symphonic music are those that remain the most traditional because they are linked to a majority of old musical works, with an audience made of specialist who does not always want to make this art accessible.

Operas can be more accessible because they follow the codes of theatres, that are more democratised, with the spectators facing the stage. People can be more or less seduced by the show. However, they can listen to the music, see the acting and can even sleep (!!) because no one is looking in their direction.

Symphonic music is in itself more difficult to access. The orchestra is the only visual show. There are no sets, no costumes, and the audience surrounds the performers. This allows anyone to watch the yawning and sleepy novices and any other attitudes that would not be appropriate.

The rehearsal room can facilitate access to new audiences

High urban densities of large cities have forced the construction of new performance venues outside of the city centres and far from their historical audience.

Between the venue and its adopted neighborhood, the rehearsal rooms are becoming places to gather and exchange where local amateur orchestras and younger musicians can play.

It is also an opportunity to open the building to a new audience and create links with it .

The rehearsal rooms should therefore be made very accessible on the ground floor at lobby level.

Providing comfort to the musicians

Transparent, windows and/or glazed façades bring natural light and therefore extra comfort to the professional musicians for whom the rehearsal rooms are actual working places. They also allow the public to see what happens inside.

When professional musicians are not rehearsing, these rooms can turn into incubators for young future talents who will come to practice together.

Turning rehearsal rooms into performance spaces

Rehearsal rooms must be able to transform into small / informal performance spaces.

They need to be able accommodate unexperienced audiences installed in a frontal configuration, with a clear separation between the stage and the audience, to focus more on music and its feelings.

Concequently, the rooms need to achieve scenographic, acoustic and safety requirements. It will be necessary to design and study the installation and the sightline of the audience, the concealment and the control of the natural light with curtains and lightlock accesses.

   Atelier Crescendo’s comment: the acoustic contribution of the seats will also need to be considered. 

A control room, part of the technical infrastructures, might be useful with open access to promote creativity and inspire future performances.

The acoustics will have to be variable according to the use of the room (it is for a rehearsal or a show? with or without an audience? with a small or a large orchestra? with amplified or purely acoustic music?).

   Atelier Crescendo’s comment: This can be done with “passive” variable acoustic systems. Read Variable sound absorption systems for more information. It is also possible to use “active” variable acoustic systems with electro-acoustic systems (using microphones, loudspeakers and special audio processing devices).

Access and practicalities

Like any space open to the public, it will be necessary to study the number and the dimensions of the accesses and the circulations.

The installation conditions for the public with emergency lighting and signage, and taking into account all the publics including people with reduced mobility.

The function of the rehearsal rooms is important. Their technical aspect is even greater as their “small” size requires optimisations. Their need for a high flexibility requires specific studies and mixed infrastructures. Rehearsal rooms are not always considered at their fair value in briefs / programs and budgets, in France and on international projects.

Design of music rehearsal rooms – Part 2: Some acoustic design tips for music rehearsal rooms

Part 1 was explaining what makes a successful acoustic design for music rehearsal rooms.

Part 2 here dives deeper into acoustic design by giving you a few tips for the planning of such spaces. It covers the following topics:

• Sound reverberation conditions 
• Volume and space 
• Room proportions and geometry
• Acoustic treatment
• Overhead reflectors
• Background noise levels
• Other general design considerations

At the end of this part, you will also find all the documents and the materials reviewed to help writing the articles. 

Part 3, written by Ducks Sceno (Theatre Consultants) with contributions from Atelier Crescendo, highlights other general design considerations you should think about for rehearsal rooms.

Enjoy the read.

Sound reverberation conditions for music rehearsal rooms

Good sound reverberation conditions in a large music rehearsal rooms contribute to: 

• the audibility and the clarity of the musical messages
• the musical intonations
• the musical tones 
• the articulations
• the balance of the sounds

Therefore, unsurprisingly, getting the reverberation conditions right is THE focus point for the acoustic design.

You need to consider:

• the overall sound reverberation quality of the rehearsal room to control the loudness and the clarity of the music played. You usually do this by adjusting the volume and the general amount of sound absorptive/reflective materials.

  Note: read Sound reverberation – Part 1: Basics if you need a refresher about sound reverberation and reverberation time. 

• the timing of the sound reflected back to the musicians (Do you remember? Part 1: The goals for a successful acoustic design explains the necessity to balance early and late reflected sound for musicians on stage). You manage this by adjusting the orientation and/or the shapes of the surfaces around the musicians and the orchestra conductor. Sometimes, you also need to add surfaces such as overhead reflectors, orchestra shells, etc. 

• the frequency content of the sound reflected back to the musicians (Do you remember? the end of Part 1: The goals for a successful acoustic design explains that musicians like to hear rythms and musical expressions that are mostly emitted at medium and high frequencies). Therefore, the reflected sound should contain less energy at low frequencies than at higher frequencies. You manage this by adjusting the dimensions and physical properties of the finishes and the materials (ex: thickness, width, length, density or also stiffness) around the musicians, so that they absorb more energy at low frequencies. 

Volume and space for music rehearsal rooms

Part 1: The goals for a successful acoustic design explains that containing the sound energy of the music is key to ensure a successful rehearsal room.

For large ensembles (including 20 musicians), the room volume should to be relatively large so that the music doesn’t sound too loud. If the ensembles include loud instruments (such as brass instruments or also percussions), the volume should be even larger. 

You shoud also set an area where artists will sit (or stand!) and make sure they are not too close to (vertical and flat) acoustically reflective surfaces like the walls. 

Norwegian Standard 8178:2014  – Acoustic criteria for rooms and spaces for music rehearsal and performance  provides guidance on the necessary volume and space  for music rehearsal and perforance spaces depending on the type of music played inside. Read Acoustic design planning for music spaces  for more details. 

  Note: The international standard ISO 23591:2021 – Acoustic quality criteria for music rehearsal rooms and spaces provides the same guidance.

For large music ensemble rooms with more than 20-25 musicians (our case here), you should consider the dimensions below.

Room proportions and geometry for music rehearsal rooms

One of the most successful shapes for large music ensemble rooms is the cuboïd shape such as a cube or the so called ‘shoebox’ shape. 

    What is a room with a shoebox shape? It is a room with a rectangular floor area, parallel side walls and tall ceiling / soffit. The base volume is two cubes located next to one another.

However, sound diffusive finishes and/or shapes should be planned to avoid creating flutter echoes.

You should also avoid any shapes that focus the sound in certain areas. This is because the sound field should be as ‘diffuse’ as possible in the room.

  Note: you obtain a diffuse sound field in a space when the sound pressure level is uniform throughout the space. 

Examples of shapes that focus sound are presented below.

Acoustic treatment for music rehearsal rooms

For large music rehearsal rooms, it is very likely that most walls need to include some acoustic treatment (or at least acoustic consideration) in the form of sound absorption or sound diffusion.

The function of the acoustic treatment varies depending on:

• the location of the walls in relation to the orchestra
• the height of the wall section considered.

Therefore, this section presents acoustic design tips for :

• the wall behind the conductor
• the walls at low level
• the walls at upper level

Acoustic treatment for the walls of music rehearsal rooms

Wall behind the orchestra conductor

The wall behind the orchestra conductor should include some amount of sound absorption and/or diffusion.

This avoids strong ‘specular’ reflections to hit the wall and reach the conductor again, creating the perception of a virtual orchestra behind her/him (see below, specular and diffusive reflections are explained).

You should favour relatively dense and stiff materials to ensure that sound hitting the reflector is not absorbed, especially at the lower frequencies due to the resonance of the reflectors.

Examples of materials are:

• gypsum based
• dense plaster
• wood particle or fibre based
• glass

  Did you know? even with a dense and stiff material, a flat reflector can resonate and absorb sound at low frequencies. Curving it will stiffen it, increase its natural frequency and reduce the low frequency absorption. 

Background noise levels in music rehearsal rooms

A music rehearsal room is an environment where the musicians need to hear their own musical details and those of the other musicians. 

Because a high background noise can mask these details, it is important to keep it as low as possible when the space is in use. 

Sometimes, music rehearsal rooms are also used as large recording studios for large ensembles and orchestras. So it is important to ensure acoustic conditions suitable for recording activites, i.e. with a very low background noise levels.

Therefore, the acoustic design should include control of noise from (some of or all) the following sources:

• ventilation systems
• mechanical systems and machineries
• electrical systems
• external noise (such as road, air or even rail traffic)

References for acoustic design of music rehearsal rooms

The following documents and materials have been reviewed to write this article and Part 1: The goals for a successful acoustic design .

• J. Meyer – Some problems of opera house acoustics – Proceedings – Symposium on acoustics and theatre planning for the performing arts (1986)

• P. Adams – Acoustic design of large rehearsal spaces – Proceedings – ISRA (2019)

• A. Gade – Investigation of musicians’ room acoustic conditions in concert halls, Part I: Field experiments and synthesis of results – Acustica (1989)

• A. Gade – Investigation of musicians’ room acoustic conditions in concert halls, Part II: Methods and laboratory experiments – Act Acustica United & Acustica (1989)

• International Standard Organisation – “ISO 3382-1 – acoustics measurement of room acoustic parameters – Part 1: Performance spaces” (2009)

• R. Wenmaekers – How orchestra members influence stage acoustic parameters on five different concert hall stages and orchestra pits – Journal of the Acoustical Society of America ‘JASA’ (2016)

• J Dammerud – Attenuation of direct sound and the contributions of early reflections within symphony orchestras – ournal of the Acoustical Society of America ‘JASA’ (2010)

• L. Panton – Investigating auditorium acoustics from the perspective of musicians – PhD  thesis – University of Tasmania (2017)

• European Parliament and Council, Directive 2003/10/EC on the minimum health and safety requirements regarding the exposure of workers to the risks arasing from physical agents (noise) (2003)

• Sound Advice: Control of noise at Work in music and entertainment – the Health and Safety Executive (2008)

• E. Hatlevik – Are musicians affected by room acoustics in rehearsal rooms – Master’s Thesis – Norwegian University of Science and Technology NTNU (2012)

• O. Riduan – Designing small music practice rooms for sound quality – Proceedings – International Congress on Acoustics (2010)

• C. Pop – Music practice rooms: Ambitions, limitations and practical acoustic design – Proceedings – International Symposium on Music Acoustics (2019)

• H. Drotleff – New room acoustic design concept for rehearsal rooms – CFA DAGA ’04 , Strasbourg 22-25/03/2004 (2004)

• H. Koskinen – Facilities for music education and their acoustical design – article – International Journal of Occupational Safety and Ergonomics

• McCue – Rehearsal room Acoustics, acoustical design of music education facilities – Journal of Acoustical Society of America (1990)

• Lamberty – Music Practice Rooms – Journal of Sound and Vibration (Vol. 60, No.1)

• R. Walker – Acoustic Criteria and Specification – BB R&D White paper WHP021 (2002)

• Skalevik – Rehearsal room acoustics for the orchestra musician – Proceedings – Baltic-Nordic Acoustics Meeting (2014)

• O’Brien et al. – Nature of orchestral noise – Journal of Acoustic Society of America (2008)

• G. Leitermann – Theatre Planning – A focal press book (2017)

• J. Strong – Theatre Buildings – A design guide – Association of british theatre technicians (2010)

• Norwegian Standard NS 8178:2014 – Acoustic criteria for rooms and spaces for music rehearsal and performance

• R. Wenmaekers – Stage acoustics sound exposure – www.stageacoustics.wordpress.com/sound-exposure-reduction

Design of music rehearsal rooms – Part 1: The goals for a successful acoustic design

When Atelier Crescendo asked Sir James MacMillan about how the quality of the music spaces can contribute to the musical creativity, the music education and the music performance during his interview, he replied:

Following this comment, it was hard to not write anything about the acoustic design of music rehearsal rooms.  

But the design of such spaces goes beyond the acoustic aspect. So, based on their experience and knowledge, Atelier Crescendo and Ducks Sceno have collaborated on writing a series articles to raise insight on what the design of rehearsal rooms should consider. 

The topic is pretty large for acoustics as there are different types of rehearsal/practice rooms to cover.

Therefore, this series of articles only consider rehearsal spaces for orchestras or ensembles of a ‘standard’ size. 

    what is considered an orchestra/ensemble of a ‘standard’ size? this is a group of musicians that includes:

• between 12 and 35 musicians.

• a minimum number or no power amplified instruments.

Also, some acoustic aspects have not been treated in this series. They are external noise intrusion, the internal sound insulation, noise and vibration from the building services. If you need some insights about these topics, you can read the following posts:

• Acoustic design of schools for performing arts – Part 1: Design aspects, or 
• Acoustic design of schools for performing arts – Part 2: Early design tips .

The first article of the series answers the question What are the goals for a successful acoustic design?

Part 2 provides some acoustic design tips when planning the design of rehearsal spaces. 

Part 3,  written by Ducks Sceno (Theatre Consultants) with contributions from Atelier Crescendo, highlights other general design considerations you should think about for rehearsal rooms

A space where musicians can hear themselves and each other 

Obviously, to hear your own instrument and other instruments, there needs to be a balance between the volume of every instrument. 

To hear your own instrument, its volume needs to be higher (to your ears!) than the volume of the music around you. But not too high either, because you still want to hear the other instruments to play in sync with them.

Also, a good balance would make the quieter or more remote instruments still audible. Whilst the louder and close instruments are attenuated enough, so that their sound doesn’t mask the others. 

   Note: We are talking about instruments here, but the same applies to voices.

But, in an environment with reflective surfaces surrounding you, it’s not just about volume. It is also about the timing!

More exactly, when the sound of your and other instruments, reflected on the surrounding surfaces,  reaches you.  

This is when you get into the science of sound reverberation.

   Note: if you need a refresher about the basics of sound reverberation, you can read these two posts:

• Sound reverberation – Part 1: Basics 

• Sound reverberation – Part 2: Specialist indices  

When designing an environment for orchestras and ensembles, you need to balance the following:

• the direct and reflected sound energy of the instruments arriving early to your ears, and ;
• the reflected sound energy of the instruments arriving late to your ears.   

Generally, the reflected sound energy arriving within the first 100 ms is quite beneficial for the intelligibility and clarity of the musical messages.

Finally, it is particularly important for the musicians to hear musical details such as attack transients. They allow to communicate the rhythm or the musical expressions and are generally emitted at mid and high frequencies.

So it is crucial to keep the direct and reflected sounds at these frequencies as much as possible and absorb some amount of low frequencies.

A space that contains music energy to the right level

Obviously, playing within an orchestra that sounds loud is not comfortable. But the main problem is that it causes hearing loss if it happens regularly. 

Most of the time, musicians can’t wear ear defenders or ear plugs because they need to be able to hear themselves as well as their fellow musicians. 

An orchestra can sound loud for several reasons:

• the rehearsal space is just too small for an orchestra.
• the rehearsal space is too small for the type of orchestra. In other words, there are too many loud instruments (such as percussions, brass instruments, amplified instruments, etc) and the volume of the space is not big enough to accommodate them.
• some surrounding surfaces reflect too much sound at certain locations. 
• some hard surfaces are too close. These can be the walls, the balconies or also the overhead reflector(s).  
• there are too many hard finishes (i.e. sound reflective) and not enough sound absorptive materials.

All or some of the above can lead to a form of Lombart effect (also called cocktail effect). The orchestra is too loud for the musicians to hear themselves. So they play louder. But their neighbours also play louder. And that snowballs throughout the orchestra making it very loud. 

A space where musicians enjoy playing and can prepare them well to perform

Sometimes the rehearsal space is part of a large performing arts facility. It can then be used by either the local orchestra or touring orchestras who need to do their final adjustments before the ‘big concert’.

    Note: Sometimes, rehearsal spaces are also used as actual performance spaces for smaller audiences.

Because every performance venue is acoustically different (this is what makes them unique!), musicians always have to adapt the way they play for the space. Whilst the main performance space might not always be available, the rehearsal should offer an opportunity to know what it is like to play on stage. 

Obviously, this is to a certain degree, because you can’t replicate the exact same acoustic conditions of the stage. At least, musicians should be given a taste.  

On a more general point of view, rehearsal spaces should make the musicians ‘feel at home’ as much as possible, whether they are from the local orchestra or a touring orchestra.

It should be a comfortable place (acoustically, visually and physically) where musicians enjoy playing and practicing. So that they are in the best conditions to communicate the emotions of their music. 

So the architectural design should be carefully thought out including:

• the shape of the finishes and the room itself.
• the color of the finishes and the furniture within the room.
• the layout of the room and of the building.
• the acoustic and the physical flexibility of the room.
• the access to the rehearsal room from other spaces of the building (such as changing rooms, restaurant, reception, toilets, breakout areas, etc) 

References for acoustic design of music rehearsal rooms

The documents and materials reviewed to write this article are presented at the end of Part 2.

Variable sound absorption systems

If you are working on a building project with a large space, you might want to use it for a broad range of activities.

Depending on the building is, the activities could be:

• amplified music performances
• quiet acoustic music performances
• loud acoustic music performances
• drama performances
• conferences or lectures
• sports events
• exams
• fairs
• and more.

The space will not only need to be very flexible physically to accommodate these activities, but also acoustically. In fact, each activity requires very different sound reverberation conditions to work optimally and ensure acoustic comfort for the users (and listeners for some cases).

   Note: If you need a refresher on the basics of sound reverberation, go to this page.

One of the ways to make a space acoustically flexible is by changing the sound absorption in the space. Essentially, you either:

• reveal or add sound absorptive materials to make the room less reverberant, and;
• hide or take away sound absorptive materials to make the room more reverberant (or more lively).

This is done with systems called variable acoustic systems or also variable sound absorption systems.

     Note: Other ways of changing the sound reverberation in spaces is by changing their volume or artificially adding reverberation with electroacoustic systems.

What are these systems? This post presents, with pros and cons explained, some of the most commonly used variable sound absorption systems, including:

• Acoustic curtains / drapes
• Acoustic banners / blinds
• Rotating acoustic systems
• Hinged acoustic panels
• Acoustic sliding panels
• Moveable acoustic panels
• Other variable acoustic systems

  Note: the following documents have been helpful to write this post:

• Auditorium Acoustics and Architectural Design – Mike Barron;

• Acoustic Absorbers and Diffusers: Theory, Design and Application (Third Edition) – Trevor Cox and Peter d’Antonio

• Sound Materials: A Compendium of Sound Absorbing Materials for Architecture and Design – Tyler Adams

Back to Menu

Continue reading “Variable sound absorption systems” →